A very large number of professional barbers, hair stylists, and other professionals provide hair cutting services in most countries of the world. The importance in society of having well-groomed hair is highlighted by significant sums of money and time spent for these services. The substantial cost of a haircut and the time and inconvenience associated with getting one makes the idea of automated hair cutting systems attractive. Today, there are a number of systems available that provide guides, cutters, training materials, and other approaches to make it somewhat easier to cut hair without the need for extensive training. Regrettably, these systems are difficult to use for most people and often strictly limit the number of hair styles possible. Simple hair length guides, mechanical combs mounted on cutter heads, hair cutters mounted on vacuum hoses, and other common approaches do not allow people to generate most of the stylish and well-groomed results they seek. It is therefore desirable to have a system allowing a person without extensive training to accurately cut hair.
In light of the benefits an automated hair cutting system provides, several attempts at such a system have been made. In U.S. Pat. No. 3,054,183, Zucker teaches a mechanical guide that adjusts a cutter head as it is moved across a person's scalp. The simple, mechanical design Zucker offers does not allow a wide variety of hair styles, and its rolling wheels or sliding mechanical guides may tend to smash some hair down, making it harder to access and cut properly. In U.S. Pat. No. 3,413,985, Dlouhy teaches a helmet fitted over a person's head and aligned with ear retractors that insert into the person's ears. Multiple cutter heads are used inside the helmet to cut hair. Dlouhy teaches a rigid helmet, many cutter heads and a large, heavy mechanism that would necessarily be expensive, bulky, and uncomfortable to use.
In U.S. Pat. No. 4,602,542, Natrasevschi teaches a frame rigidly holding a person's head and a robotic arm that cuts hair. Hair length is controlled with an adjustable vacuum stretcher tube and rotary cutter tube. Such a system would be necessarily expensive, bulky, and uncomfortable. In addition, the end of Natrasevschi's hair cutter always touches the person's head so it may smash hair down and the maximum length that hair may be cut is physically limited by the length of the cutter tube and stretcher tube. Employment of longer tubes would make the hair cutter unwieldy and interchangeable tubes, while perhaps possible, would be inconvenient. In U.S. Patent Application 2004/0004559, Rast teaches a hair cutter with some features similar to Natrasevschi. Rast also suffers from limitations on hair length and the need to make physical contact with a person's head to position his hair cutter. Rast explains how position of his hair cutter may be determined using electronic sensors, but depends on his mechanical separator sleeve (similar in some sense to Natrasevschi's stretcher tube) to determine position above the scalp. Hence, hair is always potentially mashed down, and there are clear limitations on possible styles and hair length.
It is also noteworthy that the hair cutting devices of Natrasevschi and Rast, like many available on the market today, operate by continuously operating their cutter heads such that any hair that contacts the cutter heads is cut once engaged. Such approaches lead to a noisy environment as the hair cutting device will normally buzz or at least hum through the course of a haircut and the continuous operation of the cutter head leads to additional wear on moving parts and unnecessary consumption of power.